A mitochondria-targeting ratiometric fluorescent probe for the detection of sulfur dioxide in living cells.

Sulfur dioxide (SO₂) plays critical biological roles in living systems, and participates in a series of physiological and pathological processes. Aspartate aminotransferase 2 (AAT-2) catalyzes L -cysteine to produce endogenous SO₂, which is mainly expressed in the mitochondria of cells. Herein, we present a new mitochondria-targeting and ratiometric fluorescent probe (MNP) for the detection of SO₂ in living cells. The probe MNP employed a positively charged benzopyrylium moiety as the response site for SO₂, and displayed a selective ratiometric response to SO₂ on the basis of a FRET mechanism. Biological experiments demonstrated that the probe MNP was mainly distributed in mitochondria and could be used for the imaging of SO₂ in living cells. [ABSTRACT FROM AUTHOR]